Color and viscosity of lubricating oils



Patented Oct. 24, 1950 UNITED STATES PATENT OFFICE- COLOR AND VISCOSITY F LUBRICATING OILS Paul H. Carnell, Alma, Mich, assignor to Phillips Petroleum Qcmpany, a corporation'of Delaware Application December 15, 1947, Serial No. 791,802

4 Claims.

This invention relates to the treatment of lu bricating oils to improve their properties. In one of its more specific aspects it relates to a treatment of a lubricating oil which improves its color and viscosity or viscosity index.

I have discovered that treatment of a lubricating oil with hydrofluoric acid andmolybdenum sulfide, at elevated temperature and pressure, will improve the ASTM color of the oil, and

also the viscosity index. In one embodiment of viscosity index, the color of the lubricating oil this invention, hydrogen is added to the hydrois often impaired. Improvement in color generfluoric acid, molybdenum sulfide, and oil. One ally is obtained only when the oil is treated at effect of the inclusion of hydrogen is to aid in a temperature of 30 C. or lower, and. in general, prolonging the life of the hydrofluoric acid. at this temperature very little improvement in Lubricating oil, as referred to herein, includes viscosity index is obtained. My invention incorall such products and their base stocks which porates improvement in color as well as in vishave a viscosity within the range of about '75 cosity index, at elevated temperatures, by treat- SUS (Saybolt Universal seconds) at 100 F. to ing a lubricating oil with hydrofluoric acid and about 150 SUS at 210 F., and as are usually at least one molybdenum sulfide. OIefins, arounderstood to be covered by this term by those matics, unsaturated resins, gum-forming bodies, skilled in the art. It includes, particularly, luand other undesirable components are removed bricating oil stocks, such as, paraflin-base stock, by the hydrofluoric acid, improving the general naphthene-base stock, synthetic-base stock, and properties of the oil. The color is improved by mixed-base stock, which are refined for use as the molybdenum sulfide. The advantage ofthis engine b c By blending various neuprocess is the improvement of color in the same trals and bright stocks, engine lubricating oils step with improvement of viscosity index. of varying viscosities and viscosity indices are In general, lubricating oil, substantially anproduced. hydrous hydrofluoric acid, and one or more The hydrofluoric acid, hydrogen, and molybmolybdenum sulfides are introduced to a condenum sulfides, used in the practice of this inso tact chamber for a time within the range of about vention, may be of the quality of the commercial 40 to about 180 minutes, at an elevated temperaproducts. The hydrofluoric acid, referred to as ture within the range of about 100 to about 300 substantially anhydrous hydrofluoric acid, is com- 0., and pressure within the range of about 500 mercial hydrofluoric acid, and may contain small to about 1500 pounds per square inch. The pro amounts of sulfur dioxide, water, and other importion of lubricating oil to hydrofluoric acid of purities. The words molybdenum sulfide, as about 1:20 to about 20:1 is recommended, howreferred to in his invent o mean ny Su fide ever, only enough hydrofluoric acid need be presof molybdenum. ent to make a definite acid phase. The amount An object of the present invention is to provide of holybdenum sulfide recommended is in the a novel and improved method for improving lurange of about 5 to about 20 weight per cent of bricatingoils. Another object is to provide a the oil being treated; however, more may be method for improving natural lubricating oils. added, if desired, but little is gained by amounts Another object is to provide a method for imlarger than 20 weight per cent, and too much proving mixed-base lubricating oils. Another will clog the apparatus. After contacting the object is to provide a method for improving syn- 4 hydrofluoric acid-oil-molybdenum sulfide mixthetic-base lubricating oils. Another object is ture in the reactor it is transferred to an agito provide a method for improving the color and tator where a light paraffin, such as, isoor norviscosity index of natural or synthetic lubricatmal butane, or isoor normal pentane, is added ing oils. Another object is to provide a method to aid in breaking the hydrofluoric acid-oil emulfor improving the color of alubricating oil. Other sion, and which may also react to some extent objects and advantages of this invention will with the treated mixture. From the agitator become apparent from the accompanying disthe mixture is passed to a settler unit where it closure and discussion. is separated into an oil-light hydrocarbon layer Broadly speaking, my invention comprises a and a hydrofluoric acid-molybdenum sulfide-acid process of improving lubricating oil by contactsolution oil layer. The improved lubricating oil" 3 is then separated from the oil-light hydrocarbon layer and recovered.

This process may be carried out either in a batchwise manner or continuously, the latter being preferred for commercial operation. A better understanding of my invention may be had by referring to the accompanying schematic flow diagram of a preferred embodiment of the invention.

Referring to Figure 1 of the attached diagram, hydrofluoric acid, lubricating oil, and molybdenum sulfide are introduced to reactor [3 through lines [0, H, and I2, respectively. This mixtur is agitated at an elevated temperature between about 100 to about 300 C. and pressure between about 500 to about 1500 pounds per square inch. The treated mixture from reactor I3 is passed through line It to agitator it where it is agitated with a light paraffin introduced through line H, such as, isopentane, to break the hydrofluoric acid-oil emulsion. From agitator it the hydrofluoric acid-oil-molybdenum sulfide-light parafiin mixture is passed through line 18 to settler I9. In settler [9 the mixture is separated into two layers; an upper layer of treated oil and light hydrocarbons, and a lower layer of hydrofluoric acid, molybdenum sulfide, and acid soluble materials. The lower layer is passed through line 2| to fractionator 22 where relatively pure hydrofluoric acid is separated and recycled to reactor l3 through lines 23 and I0, respectively. The acid soluble oil and molybdenum sulfide are withdrawn from the kettle of fractionator 22 through line 24 to a molybdenum sulfide recovery unit 26. The recovered molybdenum sulfide is recycled to reactor I 3 through lines 21, 28, and E2. The upper layer from settler I9 is passed through line 29 to fractionator 3| where the light paraflin used to break the hydrofluoric acid-oil emulsion is separated for recycle to agitator [6 through lines 32, 33, and 11. Other relatively light hydrocarbons from fractionator 3|, formed in the high temperature hydrofluoric acid treatment, may be recovered as by-products of the proces through line 35, or recycled to reactor 53 through lines 36 and II. The improved lubricating oil is Withdrawn from the kettle of fractionator 3| through line 34 as a product of the process, and may be caustic-washed and/or filtered, if desired. Any small amount of hydrogen sulfide formed in this process by the reaction of a molybdenum sulfide with hydrofluoric acid may be suitably recovered as a by-product of the process.

Any suitable equipment may be employed in the performance of the present invention, and particularly equipment which is resistant to the corrosive action of hydrofluoric acid. Conventional contacting equipment, similar to contactors which are commonly used for conducting the alkylation of aliphatic isoparafiins and olefins, may be used to provide suitable contact between the reactants. Any other means of maintaining an intimate contact of the lubricating oil and acid-sulfide phase may be employed. The equipment should be provided with means for maintaining the desired temperatures and pressures in the various zones.

To further illustrate some of the many aspects of this invention the following specific example is given.

Example I A 4 liter steel bomb was charged with hydrofluoric acid and a mixed-base lubricating oil. In particular runs, molybdenum disulfide and/or hydrogen were also charged to the bomb. The charged reaction bomb was fitted with a suitable pressure gauge and heating equipment and then clamped on a platform rocker. The bomb was heated and agitated for a given contact time, and then allowed to cool to room temperature. After cooling, the bomb was charged with 1 liter of isopentane. The resulting mixture was agitated one hour, and then removed from the rocker and allowed to stand in a vertical position for 1 hour. The acid layer was withdrawn, and the hydrocarbon layer was washed with caustic, filtered, and topped to the initial boiling point of the untreated oil at reduced pressure, to remove light ends. The following data were obtained.

Run treated I 2 3 4 Oil HF, grams 581 595 994 009 Oil, grams 869 865 876 873 Molybdenum disu grams 50 50 Hydrogen, p. s. i 200 300 Contact time, minntes. 120 120 120 120 Contact temperature, C.

(max) 172 174 169 1 8 Contact pressure, p. s. i.

(max) 740 960 650 080 Physical Constants:

Viscosity, 100 F, SUS... 388.3 335. 9 342.0 348. 8 343.3 Viscosity, 210 F, SUS. 55. 52 54. 93 54. 59 55. 20 55. 00 Viscosity index (Dean dz Davis) 101 96 08 98 API gravlty 28.4 30. 5 30.1 31.0 30 4 ASTM color 3% 4 4 3- The data from runs 1 and 2 show that treatment of a mixed-base lubricating oil with hydrofluoric acid at elevated temperatures and pressures, in the presence and in the absence of hydrogen, produces oils of improved viscosity index,

but impaired color.

The data from runs 3 and 4 show that treat ment of the same mixed-base lubricating oil with hydrofluoric acid and molybdenum disulfide, at elevated temperatures and pressures, and in the presence and in the absence of hydrogen, p duces oils of improved color and also viscosity index, as described in this invention.

In runs 2 and 4 hydrogen was introduced to increase the pressure within the bomb, and to prolong the life of the hydrofluoric acid.

Although the process has been described and exemplified in terms of its preferred modifications, it is understood that various changes may be made without departing from the spirit of the process as disclosed and expressed in the claims.

I claim:

1. The process of manufacturing a lubricating oil of improved color and viscosity index, which comprises treating a lubricating oil with a mixture of substantially anhydrous hydrofluoric acid and at least one molybdenum sulfide, the ratio of hydrofluoric acid to oil being in the range of about 1:20 to about 20:1, and the quantity of molybdenum sulfide being in the range of about 5 to about 20 weight per cent of the oil being treated, said treatment of lubricating oil taking in the range of about 100 to about 300 C. at a pressure suflicient to maintain the oil and hydrofluoric acid in liquid phase which is in the range of about 500 to about 1500 pound per square inch, for a period of time within the range of about 40 to about 180 minutes, cooling said mixture of oil, hydrofluoric acid, and molybdenum sulfide, introducing a light-paraffin to break the acid-oil emulsion, and recovering an improved lubricating oil as a product of the process.

2. The process according to claim 1, in which the o ybd num sulfide used is molybdenum disulfide.

3. A process for manufacturing a lubricating oil of improved color and viscosity index, which comprises treating a lubricating oil with a mixture of substantially anhydrous hydrofluoric acid and a molybdenum disulfide, the ratio of hydrofluoric acid to oil being in the range of 1 :20 to 20:1, and a quantity of molybdenum disulfide being in the range of 5 to 20 weight per cent of the oil being treated, treating said oil at a temperature in the range of 100 to 300 C., a pressure in the range of 500 to 1500 pounds per square inch and for a period of time Within the range of 40 to 180 minutes, accomplishing said treatment in a hydrogen atmosphere, cooling the mixture of oil, hydrofluoric acid and molybdenum disulfide 15 and introducing thereto a light paraflin to break the acid-oil emulsion, and recovering an improved lubricating oil as a product of the process.

6 4. In a process according to claim 3, the use of a hydrogen atmosphere under a partial pressure of 200 to 300 pounds per square inch.

PAUL H. CARNELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,366,743 Matuszak June 9, line 2,378,762 Frey June 19, 1945 FOREIGN PATENTS Number Country Date 292,932 Great Britain May 23, 1929 

1. THE PROCESS OF MANUFACTURING A LUBRICATING OIL OF IMPROVED COLOR AND VISCOSITY INDEX, WHICH COMPRISES TREATING A LUBRICATING OIL WITH A MIXTURE OF SUBSTANTIALLY ANHYDROUS HYDROFLUORIC ACID AND AT LEAST ONE MOLYBDENUM SULFIDE, THE RATIO OF HYDROFLUORIC ACID TO OIL BEING IN THE RANGE OF ABOUT 1:20 TO ABOUT 20:1, AND THE QUANTITY OF MOLYBDENUM SULFIDE BEING IN THE RANGE OF ABOUT 5 TO ABOUT 20 WEIGHT PER CENT OF THE OIL BEING TREATED SAID TREATMENT OF LUBRICATING OIL TAKING IN THE RANGE OF ABOUT 100 TO ABOUT 300*C. AT A PRESSURE SUFFICIENT TO MAINTAIN THE OIL AND HYDROFLUORIC ACID IN LIQUID PHASE WHICH IS IN THE RANGE OF ABOUT 500 TO ABOUT 1500 POUNDS PER SQUARE INCH, FOR A PERIOD OF TIME WITHIN THE RANGE OF ABOUT 40 TO ABOUT 180 MINUTES, COOLING SAID MIXTURE OF OIL, HYDROFLUORIC ACID, AND MOLYBDENUM SULFIDE, INTRODUCING A LIGHT-PARAFFIN TO BREAK THE ACID-OIL EMULSION, AND RECOVERING AN IMPROVED LUBRICATING OIL AS A PRODUCT OF THE PROCESS. 